My SO has night terrors (yeah, I know, only after she started spending time with me) and once was analyzed in a sleep lab (to no avail) for it.
I have very vivid dreams, which frequently don't make lasting memories but occasionally do. The individual segments usually make linear sense but the way they flow doesn't. Sometimes they are wonderful, sometimes they are horrible. A high school buddy and a long-lost wonderful girlfriend make frequent appearances. So does anxiety in one form or another, including the classic exam dream. Tonight I fear I will dream that my TV will only get gymnastics and diving for the rest of eternity.
Sometimes I can trace dream content to unfinished business of one sort or another during the preceding day.
In high school a friend (not the same one) and I did a sleep and dream monitoring study for our science project, each of us staying up all night to monitor and take notes on the other's sleep and reported dreaming. We followed the classic pattern of intermittent dreams getting longer and longer before waking.
Did you see the great David Lynch movie Mulholland Drive? It only makes sense as a dream, and then it makes great sense.